Diborane ignition

The diammine complex of diborane (formulated as above), though less reactive than diborane, ignites on heating in air [1,2],... 

Borane (sometimes called diborane) ignites when in contact with air, so it must be covered with tetrahydrofuran, always. 

Opening of a bottle where some particles of lithium aluminum hydride were squeezed between the neck and the stopper caused a fire [68]. Lithium aluminum hydride must not be crushed in a porcelain mortar with a pestle. Fire and even explosion may result from contact of lithium aluminum hydride with small amounts of water or moisture. Sodium bis(2-methoxy-ethoxy)aluminum hydride (Vitride, Red-Al ) delivered in benzene or toluene solutions also may ignite in contact with water. Borane (diborane) ignites in contact with air and is therefore kept in solutions in tetrahydrofuran or in complexes with amines and sulfides. Powdered lithium borohydride may ignite in moist air. Sodium borohydride and sodium cyanoborohydride, on the other hand, are considered safe. ... 

The situation does not improve with mixtures with the hydrides of the elements. Thus, a detonation occurred during contact between water and chlorine due to an accidental spark. Phosphine, silane and diborane all combust spontaneously in chlorine (their behaviour is the same in oxygen). With hydrogenated nitrogenous compounds ammonia, hydrazine, hydroxylamine, ammonium salts (especially ammonium chloride), and also sulphamic acid (these last two in an acid medium) there is ignition or even detonation. 

The material (actually an equilibrium mixture of diborane and highly ethylated homologues) ignites in air. The propyl analogue behaves similarly. 

Arsine, phosphine and silane all ignite in contact with chlorine at ambient temperature, while diborane and stibine react explosively, the latter also with chlorine water. 

The reported ignition of diborane and tetraborane(lO) in contact with air or oxygen is due to the presence of traces of silicon hydrides [1]. The lower members of the latter class ignite or explode in air or oxygen, especially at reduced pressure [2], Phosphine is also sensitive [3],... 

Great care must be used in handling diborane and alkylboranes because they ignite spontaneously in air (with a green flame). The solution of THF BH3 is considerably less prone to spontaneous ignition but still must be used in an inert atmosphere and with care. 

Diborane is highly flammable and has an autoignition temperature of 125°F. It is also moisture sensitive and will ignite spontaneously in moist air at room temperature. 

Boranes oxidize in air to form boron oxides. Diborane spontaneously ignites in air around 50°C. The presence of impurities can lower the ignition temperature. Tetraborane decomposes slowly at ordinary temperatures but rapidly on heating. Decaborane is very stable at ordinary temperatures. When heated at 300°C, it slowly decomposes to boron and hydrogen. All boranes decompose to their elements at elevated temperatures. 

Western States Sect Combust Inst, Paper, WSCI 65-23 (1965) 27) G.R. Mistier T.F. Seamans, Vacuum ignition characteristics of flox/diborane and oxygen difluoride/diborane, NASA Contract Report 1969, NASA-CR-100678. Avail CFSTI. From SciTechAerosp Rep 7 (12), 2196 (1969) 28) W.B. Powell et al, ClFj-Njli, liquid propellant evaluation and rocket motor development, TechRept 32-305, Jet Propulsion Lab, Calif Inst Tech, Pasadena, Ca, (May 1963) (NASA N63-21722) 29) H. Allen, Jr Pinna, Relative ignitability of typical solid propellants with C1F3, NASA TN-D-1533, NASA, Wash, DC, (Jan 1963) (NASA N63-11616) 30) R.F. Sawyer et al, AIAA J, 6, 11, 2111 (1968) CA 70, 13118 (1969) 31) M.C. Branch ... 

Keller, P. G., Inorg. Synth., 1977, 17, 34 It ignites in air, like the parent diborane. See related BORANES... 

Mellor, 1939, Vol. 9, 55, 396 1939, Vol. 8, 65 1940, Vol. 6, 219 1941, Vol. 5, 37 Arsine, phosphine and silane all ignite in contact with chlorine at ambient temperature, while diborane and stibine react explosively, the latter also with chlorine water. See Ethylphosphine Halogens... 

Chlorides. Contact of 75% phosphoric acid containing traces of chlorides within a closed storage tank may liberate hydrogen, which will explode on ignition.3 4 Nitromethane. Mixtures of nitromethane and phosphoric acid can be detonated.5 Sodium Borohydride. Generation of diborane by addition of sodium borohydride to anhydrous phosphoric acid may be dangerously violent.6... 

Use and exposure Diborane is a colorless gas at room temperature with a repulsive, sweet odor. It mixes well with air and easily forms explosive mixtures. Diborane will ignite spontaneously in moist air at room temperature and can cause explosions. Diborane is used in rocket propellants and as a reducing agent, a rubber vulcanizer, a catalyst for hydrocarbon polymerization, a flame-speed accelerator, and a doping agent. Diborane is a very toxic and flammable gas used by chemists to make other compounds. It is also used in electronics to impart electrical properties in pure crystals. Industrial workers are exposed to diborane by breathing in its vapors in work areas. - ... 

Bulk aluminum may undergo the following dangerous interactions exothermic reaction with butanol, methanol, 2-propanol, or other alcohols, sodium hydroxide to release explosive hydrogen gas. Reaction with diborane forms pyrophoric product. Ignition on contact with niobium oxide + sulfur. Explosive reaction with molten metal oxides, oxosalts (nitrates, sulfates), sulfides, and sodium carbonate. Reaction with arsenic trioxide + sodium arsenate + sodium hydroxide produces the toxic arsine gas. Violent reaction with chlorine trifluoride, Incandescent reaction with formic acid. Potentially violent alloy formation with palladium, platinum at mp of Al, 600°C. Vigorous dissolution reaction in... 

Ignition on contact with carbon + sulfinyl chloride (when ground), nitric acid (becomes violent), viton poly(l,l-difluorethylene-hexafluoropropylene), chlorine tri- and penta-fluorides (hypergolic reaction), diborane (forms a complex that is pyrophoric), hydrogen (above 300°C). 

SAFETY PROFILE Moderately toxic by inhalation. A severe eye, skin, and mucous membrane irritant. Explodes on contact with dioxygen difluoride. Violent reaction or ignition with borane, diborane, F2. hexafluoroisopropylideneamino lithium, O2. Win react with water or steam to produce toxic and corrosive fumes. Dangerous when heated to decomposition it emits highly toxic fumes of F" and PO. See also HYDROFLUORIC ACID, FLUORIDES, and PHOSPHORUS PENTAFLUORIDE. 

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